SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82b4d81fa71d7466a8f5837be7514602a1d9a33f3a5683ff9850afeb03891411' 
  AND token = 'PtiljAkvfrTzuOfcuvCR+L94FyLzTuQ36/iOUPB5jYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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