SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '491c45dd75adbbc1982535429f4bdb73d74ce91fe753dae12089ca369bc20768' 
  AND token = 'cpzq86V3HSeuuuW+F62sTRM82fiPHDBezdPcFSBIvas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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