SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c888c3414c6369769f5ae1bd02c67be54ecad7a6cc84d0c74cee2a8e5abeac23' 
  AND token = '1YZbIMNuak9Vk0mXTZiNDbG9PYDQWfQB/AUcdrMpAho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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