SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19a3beeee49329edde947abc0a637cf13dc7228e9265548851f69a15848800c5' 
  AND token = 'MUvfqXEkDSTfTG97LTuEqyVgVc4Hkwygyhy1/q20kfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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