SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb6ee0049b67654642ae442c74f5d4a18797c7b5f86d83d74c2a48fb09ab8026' 
  AND token = 'qmIsPBIad+D6weDAdQsEShdijlABQK0FpnsgtARCOzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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