SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '075f629233d4cf46228d9319ca5579e1d86816f8c88c04cbdc23a65fedb72d42' 
  AND token = '3T0gNqmp3s7bj8pU/YaQV1dDJmgB7UeMhZrmq6BiH6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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