SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb011538387917c29ef4f5e7806a8a8bf52bd93a5dfeb4bec4195a9d8a744ecf' 
  AND token = 'JsDBqxXBQp830NDZ6ceB9j0OlX+FJgrwz7hVMCR6sTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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