SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e90c9329097369aa06977fbc12e628f2bd945b19f01bf812e1b26dcc3885b2f8' 
  AND token = 'hfE3boFFYYawE7jJrsYGzKAyHcvKY55WCY6to3CJebM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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