SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd44fb94680d89e12058ff350d515e1857535e10147d519dd6e0ef23288fb84b' 
  AND token = 'rX6U6trh/cEmoj36/Gc9QVgxhKOHS3DfHJwOCo9v3gc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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