SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dadd555c544194e9b9a57e7833c34b858f3b24c83908caca097f25dc587e936b' 
  AND token = '4YJsMNcTlP8Y3TXmBxGi2phWGX+6EIw7jVLjBwdjkH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}