SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3441d66e58c98241acabfaba2e2a65c53fcb8da31601ff67668f03e1bdfcd87f' 
  AND token = 'yVhvKqdaQylk9CwGrgl7Hj+e5LpCN2lkbWIBZmCk0/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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