SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '108a28bb70ba1a9f1f727dc0d503d90365ce98fe08b4b1445a5b7d81f88733aa' 
  AND token = 'r38jVSa+4Xp+HRqGooim6GfOrciUtKU0PJ7X/doBLpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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