SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbde23543ed5d21fa960fc0664486fbcba6851a6d871b76bd228e68d3aca1944' 
  AND token = 'PoufC8CYkpG3w9QIVmFT/dKCFGKIPjtM0ZnXYh/YmA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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