SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d8b6bb0666f54da4a3b040fc32030a30a88079206ef1aae0b017bac4e915b84' 
  AND token = '1+yGWjuAoxrJV2gxv7oxpccFHQ4MVs7ULTJCAXzi0iU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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