SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91275dd631afb5fe511f882308b33edbef7605bedc31f4d6f5b3f15fd15abc10' 
  AND token = 'GUov0iQH/iJ9Cnr/odbk8ETyv9KcOJU5rNizLOuiynI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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