SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '790abe888a33c779d70eb07a8f68043a214a226e4e2d1dea4b2ddfae3ad06871' 
  AND token = 'HJvGcPBpkKL1b5KagbUnn+V2HsUYdSUmbP7blpXJwlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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