SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4b01db358591846d6802f73ae73fe84b9a91dca86cdcd3915e3c3d6f2e2100d' 
  AND token = 'B84EjiqbhKWDYQ9cGRF/hNL1TF6BCFllXdMqCAcoht4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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