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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76a2471fceb6e9df0d50c961e6dbc954fea51500d4a3e5caa2af96af654ffa77' 
  AND token = '4PZsTCNax8mGmbbUvHYeVEc6H+yu02ZQq3waG/1ZL+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}