SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdbf731b8687cf554f41007dcb9a823756c29f1274a9e00f312238ece57894e5' 
  AND token = 'DC6CoJQvHwJljP4mrmuHXrtsrPh/lAij4eIKuPoJiC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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