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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21037528b0470eb712d3614d466dc65051735e43c1d146a0bfb0b9e5d2e8ac2e' 
  AND token = 'Ml27Et63TxvEO9cuk9lZBfowHtRJpVDr7ua2wxd1ABo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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