SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b927f5f9550471c08f8ec8624e708edd6e1dbcd4fb10670361dc7e4b41ee64ea' 
  AND token = 'fkACkrOy02CP+JPfsMOFTctb+cO7c8iIYU3IKpSAJNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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