SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9baa95310fe6506523802064dc8e3291692b3da6c2406bdee4b5a5bd9c9b960' 
  AND token = 'CmIL0JxOGZW1IV9ddVeb84zBVYgYnA5tjRXtLNupqjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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