SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89675e69e4d0c3f7d4d8bb439fce5ebf7db94ccc8df1cbb1e884b98ac3ca9395' 
  AND token = 'mhOcjdraMfFr0Mz3muwJSqXW5XpLTb1zCESgneQEdUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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