SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '287ac93a04fe6a50f4775b9ab17aeb2750e4ac31e6ef74e88def590345d275f4' 
  AND token = 'S6ayp33gQUJTLnknfxJizOkTYRLE/W51WBmbE2W6T4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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