SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '854a68798f12caf05e3445e869a5a187275166debe38ce59b089d17f27d36b2a' 
  AND token = 'fXLTTdL0ZSXWRSUqZtLNN2uQjjMlbl+Yf1/FJujyA7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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