SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7972a4631e807725dea11d0cfba16bb278d96b98fffb9544386d1c9c9e7f1d43' 
  AND token = '5hnhTA9z7EgDr5oX15yqzl3D6rOL+CA2QuHQk/HICkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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