SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '314920086ee6d703ea132aa538622f49a94ddb4a8443c6c92da115dae7679b10' 
  AND token = 'blOAHVGdoeGyX7s3jEPmqtEycqpQmnLrfgdpfYOiogs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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