SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db6e9099ee84c4e4a05937f2bb9bf46b3eb1d37a7852e37042300e8a2bb8cc75' 
  AND token = '5JqGtUFNuAdGgCJBds92Le+hUsjlZHvUm8PQSkRMTW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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