SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af977d673186e572e8c20e1be9be82fc587ad80d8572acbdcfaada1730686dce' 
  AND token = 'egZgwF0q8gOCjKCgUxsdjgOWWZ9EmUR60a030HtVQ8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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