SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19d79f08f685edcaa4de4c7e122617f6013b089b66bdf43f51a7b056a9931388' 
  AND token = '8KdNyASIvVbGA36f2MIeX4AeC9HJj47I1aRmjR9Qejw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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