SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84000742b94c13f9e8f036bdfd91b9b8adde6cdd0357e92ebb1e1c5788df372e' 
  AND token = 'wA/+ixT/icjaEzQpqqtj0Al2ovTpaIk15neZngcTspU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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