SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a54026e9da19101880d92c5bb9c5f39da02e2db6c2ba09969e303c697551c460' 
  AND token = 'FXFCqMlRSoGsLoPpM2z4sMyOa006PdtR0wKtQMhT8Q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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