SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb1263ae1c5db5d5a1d4906057c0a37d3e9c29d7eb257f8f58ddb749033aa4f7' 
  AND token = 'l/J1CS6l2TsGwrnPR9Z60tmwueSGkOUjI2gB+wJRGUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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