SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4747d00a8b0c1b6e548e7ef241f78757e062a3bec85f515315b67609157ec99d' 
  AND token = 'dKHpy8DuQ6jribkUXutWAYvrLl3L4j1JT6C9+m7p/Vw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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