SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cb9ad55fdcf7e453cc919c047cb26351cfc704e8afe6e96789365632622abbd4' 
  AND token = 'R+iuf/Nv9YFRGoFD1UC1Zj4c8L0b8ywEigHcTtK1V94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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