SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c1a6ade7e878ac941145cb46f34aa68bfdaa083055b9a062c7538e34ab55407' 
  AND token = 'hSNQUr9Gjsi89jOXr674AlDtiqZwwyuIg1w9O2EwjFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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