SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cef1ab63d09a337c0edafb20be1a077075f6978f5299c10e45585d16a0cfffcb' 
  AND token = 'tP7Bk1SmQy3/ZPTbt8qqHvXeBkfhOeI6wIWnaIW9GTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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