SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18fbb44c6a918a5c750fdfb16ae427ea9594832067dcec4381c5d073b43687d7' 
  AND token = 'YbwBNBYeUKex1B/xQAjYbJULtmsoiVuzjlWJp+20+qQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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