SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb9cfcdf76d82a7e8218524c0700dfa70072db407f316dcbed506a90bd817472' 
  AND token = 'o21AsvRkfL8xVKPwPN7MbUbpTRf3Wz9Ah2+tPKVoEi0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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