SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de0df217396bb928a9bcadb5870c1a0ae8830160a4017a79aac99e2eca9f321a' 
  AND token = 'e8Tz/+hNrslZtggJr6Hgw5ExKRkx4+JnzwmFmu6mZzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}