SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae3575d663526551270337b9f8617cb28c4c7954a0cb2049bbf56d463d1e2f93' 
  AND token = 'VjThINbhaO5qc+85iWJXhp7OihFu5uSpvK5M01AbKYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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