SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02b974fd4d8e88b8cdfb940e74b397511e1d57d134d638fad5353f03c88ec171' 
  AND token = 'YvGt+cDRrb32pBtzN9P4agrp5cjcB0bZgqx8L0kfKtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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