SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '31406323860641432a59af186001aa78338ecd260d5122cac3be0048ecaab59f' 
  AND token = '5Md+YruscGYtUymg1dfQzKlk5YD5NfRFSILTomq4GVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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