SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86a9a6c5f1c2f17cd83bc9a7514a8cdb2f9541920fbaed08fa1ccefc2fafd386' 
  AND token = 'cQ6I/xKGVIH/vGAudPYemIEXuVuwHXg+HIiKVFCUvK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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