SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10ca4b5ff56235da726f878414d4d7871013e404ea9f2cfef9650894911015f2' 
  AND token = '8zGSczyrotkNLcYrWD2jij65DawYUxRF1AGqYlYYyvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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