SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74641e2299f1ebbfecc9428d8aedba6de3c71c8efadccc53f6e490f9151bab00' 
  AND token = 'ZfIKHoOe7DuFa5kNkHF+s6rqhhBu/+UZVl5SUZzr6Cc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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