SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f35ee5128828e807b901378bb118b025cc47adeb102f8c13b0151dc1b8aa28dc' 
  AND token = 'UoW4o+fQFMMUoA2XOWDyk5vPyqWlQ2Qy2XEfCg5ymzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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