SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fa9fcf30960d519f180c3441ce87f25d45040806992704f1b88a6beb51937e4' 
  AND token = 'CmHI1SNsSxBiVwEAYVyvSeALQtOUWfjKJ/aBZuRzSkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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