SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '29f3795d1f0261ea5d9931e855e27185f75694a54e2290af22c7947ebe15bac5' 
  AND token = 'AjnCSYmAmDWrYjh1dyOyZGwjGsP3fRdapdzIx5nc8DA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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