SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf3de641a005de194fcf12cf7a37e3a7c0c3511f4a3abb0ea1de276e0b744631' 
  AND token = 'TV1E0YWKxAJiyUQJCzyuUxvi0pRDc4trUD5vTQsqLcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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