SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fa64a7112ea468d29aae41a482c4b3269cd7522f2ddb18fdf2cd6ed84a01676' 
  AND token = 'UDLT1RdQzp69/YEyHkTSpmqzlFT/SS4+YbH16NHNZms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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