SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec3c990946881bf1b97bd8c44ce3393cefa33eded8bcf4cd903888b17d50d121' 
  AND token = 'MdFqjvxV5yOLxfXX0uSya6cRNKYbcW/HZVgM6D9DELw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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