SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf8115c65430ebe4ae99175003df8b3e8ce104f7f03dac5a5af51bc3e22b235f' 
  AND token = 'IVk/hqJvAolSbGiegfTPVXjmv8wDvOJCkc4Kh0l4lYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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