SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f415040def813ee5adc70d0591920519a0a59395ecb6831cab1c4dc1388e2b16' 
  AND token = 'RElBzEPSXBncoiP0Ipy9UqK9vq4IDFdAwVZlNfcB2eQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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