SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90a0e5942173e34cf026f8d910a84ef97b77345485d7c1e276d223d479e1f80b' 
  AND token = '3zahHtwju5JuyruKFigradvqWvOyj3DYG8yQ9nOKPDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}