SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58ff2d9795f09ed9596400509798025239c1be91c86b3eb63b8ffe56f3154794' 
  AND token = 'wec48dXKgfqpR9ChqwWRFlugvkZfTe/YrjgUv5Kz3M0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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