SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81437df1f6b4c68ad0c8b779f42f7d0af1537fa547b8c81c5eb4d0de9d906cd7' 
  AND token = 'VpnIkHYNpVhqDmuZfPQTFODqFhFYJ9ZygUcEc7bH8+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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