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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e12cdda996381bb1db0c06536da3872913e076fa5c59b65ce3faf19e022aac2' 
  AND token = 'rM974hjd1i461UYLXloCHKrPJsYqHA8w2hewwKTC7h4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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