SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19aa840e386a4c67f6cc33ddd59188ed4181c890b7a3b4365b0ff0e55e3146d0' 
  AND token = 'u1lLJvdYI0Uxr4VV9ink2Z/eWMkxjjl6JSWd33Wytjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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