SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd35dff55a3d663f2579bbf5268ee477ddbf14d04f482dd899249bd8d66c28c65' 
  AND token = 'vPaShEYcBSOcxLKwF5yB2KeuK9fV0DGwCNHOvgP1Woc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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