SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4551904f01cf8f483c82efeee102b17acbbd3b2351f399e7717e6a4612ef80fa' 
  AND token = 'DhXIwbBsDs2zp5nFR2pEW6h2ZPBCIimSqAP8TTaNDq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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