SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c935464ef8fefc5fa46b76946e69ae8b98f79cbd29da92acebe34c8515ea2bf6' 
  AND token = 'T+LBg8nHxiDgChjmTGu92VWDeuMje1W81qSePd+TCAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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