SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16519d0e0d98f7cb6f09b603fba580748079291dda07221a7a35f5d8e3dbc512' 
  AND token = 'gZlf16qcs3Oxixd8AplsnbqZsKJGnGvO+Z0587Guiow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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