SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '870d36e2eaff7f0b7f0692ccfabdc09a753d9efaa00c9e5c8d5153019e375d9b' 
  AND token = 'Hrg3nDsmrKd3wpRHIbrvHhNtAd4dOs+CZ79QYFkaaIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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