SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '606f4b74759fd962589d25294eb82b63587ba6fda0db03b8e355f2219ffea73f' 
  AND token = 'XziNwpqDFfL4Md+5AFAYR7sLK7rP6fjX3nbQaddXKDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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