SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '035017f6f102c03444903d70316fcabe8cc9a177c29e1a9fe4f0bf6115a49583' 
  AND token = '7f+xQUlDJOgYLYVqq+BQR75YvKmyzf04nF4u2ihfmKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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