SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d83cadfb14587d96148385b6279adcbb2487e7b4ab8c68dbd06d279b1b3c037' 
  AND token = '0oYi39E+aD4okjwCR48Zp5n3qZgZaPZr3nuZfCM+tQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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