SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df256156773b1f84be346919c9863a4a9277a2ca3d4733cfaec7b27831c8a196' 
  AND token = 'zqIhvrIQGp3ETdcfQuTHwQNAuvlGtkRJmfBOCVVPZm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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