SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f227d468f8e420a2b7bbf998561e263fc0d32652583b0ea1263fd6e2acba216a' 
  AND token = 'UDHqpG1Wazb7tt9+N5N084JxT6vp12SFvqlI1JoMljY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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