SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a4790b8186385215602c5cccc5a3bf054b1c6a01d5cfd168112d41a95e4f477' 
  AND token = 'Lh6o3fLTip+UQPz/m6nVMzRx3Ar6cQWowU/fIHEE31I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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