SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f97787c2eb1336e23342c68e0a87d84d769d76252765961cfbbf0c9e89e480a' 
  AND token = 'VfS1XXreX0r15gwRS6RTGY16DMvQ9pjZ9LG/gF0H9EQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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