SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6d0393e1f229ad9c372d1512020e4b9f9afacd212fae5ae037b0ab955515950' 
  AND token = 'iaA+Jj14UuSCjr90uARXLPTdNfl/7bVk/fZnG6kNoGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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