SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1f8977ae0ff3c11221753937ea99cf0ba1452aa8315b5493fa5139b0fa80f62' 
  AND token = '5Wb8agjqFpYi0WR4td3feZAcPPLCrMkIhuY0b+shf5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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