SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efc4ae98aa3df693d10ba764245598e182308ba0dccecf87e2dca50e46532374' 
  AND token = 'Mkqh4nDguk5j8rNW2jwGHNnyKL7OB/ySj1TQt+IWpLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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