SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '266ed7efe8046ec26f86d59b91063dfbc63b7a960be990785eae8c70a0dc3fd7' 
  AND token = 'mhTWAhU0VGszTv7Gj1WG8WdHkCJT8eQSHXLAa5paNnA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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