SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a9459faa847f906c653a9d0048104b63192054e24fb85184330a88f0c4ab3e4' 
  AND token = 'qDLmPIfg/OjJa6o4qt2MFb5RkOK8Yp+PQefCtFGEmts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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