SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42303959179fcddc102999700524eeb2ff2d6bb2b31040862796dce629efbaa0' 
  AND token = 'CWVsvcLX7IGtNb5nfHn6jegYYhpOObNhb5AFknsQs04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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