SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b05373dd7146c0c4b88df136b1547eadfbcc7deed066eeb64b551cb072de91d5' 
  AND token = '3vUWdXOIRSl7LhPGDH+tWRJdUkvpfQ3AvQIesuoxTQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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