SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b570a3d183a12cc75680513e804319a55d35c76e21d7985ec2da309dfc735d6' 
  AND token = 'C5spSQwsHILs+/k8eaqIBpKwyumcdKFKMFPDkE8Z7WI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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