SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ebd4b1242c4c32b8a6c0340b78e35ba5d251bfc6d50ea5bfe175c798d541837' 
  AND token = 'yV5/s1OVwwmLqqYv6Zc54KYyxrFypIEWKbhJA8dztDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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