SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c817f5383c73be59a4eb5264d2e01b75644a872c34535f2ab8edc77072f313f' 
  AND token = 'HOQyQFkgORJIxnQJCgoSVaEC3kHipb7bfnoqUvAAOe4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}