SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6afd2ef56db69f2f416e408f237057903f15d6605e17babf49e77c4da502550' 
  AND token = 'bQQPtZlDN668YFdOB9wta0bnVrTNvwDKY5eKI/hOJkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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