SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '354b2672ff03c330d6edc3d4b148638ccb855ec8f4a9243de388e1a307456383' 
  AND token = 'QVHDbg4ssxBEktVXPlOMfj+HaWWqPdCoEZYk/lZDMnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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