SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '778618fd42f84dc2dfc4beea9fa1ac38b5f03218707af7fbaa5ece100abc336b' 
  AND token = 'EXANQbKNfw916e7KNaK6nXWJIonSh7g1BuN7McvXU9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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