SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b6a4432503e24fbc9a3087e681ac580bacdf704833b95de02aceee20fa33b95' 
  AND token = 'NxINND5a9nfh1fVBT0c06Zt2XxnV3RZ1eTEfNpruvk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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