SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cedf56c7857b7dbec889a939016065328513c82bb0657075dae5ec97d4faee8' 
  AND token = 'LuuYHgoexHR5jJievq68TG2vG65BHGxFx7mDIHNXhFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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