SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '501a35311326aa16a7b9d0219177e22404b12c5689a807ebaa4d7ede058cbb4b' 
  AND token = 'XR+++tGjfaBBcg5gRWhQ9nNn1Zkmcd47gKqyeFk3oTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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