SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f878978f556b32e333b83a478c937fde58bdb8adeb7fed591c0f9fc724ca171' 
  AND token = '2TZWIgpiwSs7jUEtmxC//fniwPkvIk6iMOJOWzFBLP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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