SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e60be2778defa4c8d113f50d05a05639ff8fa182995ed4af895ba4eb7b402bd2' 
  AND token = 'SSyev9RDO1UVOk8nLrz+iOZ7u/5YxVpCmVxcEXf+aC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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