SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd403c29d9305a516ab411ec9b6ecfbbebee5200b749949a6daf32c6ac70bb1b2' 
  AND token = 'PK/wFyvJBnMQSk2GKVYOh0R/la6VZm6YyxGHfkaH08g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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