SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1da78706ac7ac3292d979434d687c5c07897806060942e64fa697c4ddb92f00' 
  AND token = '6fLI8g9Ou3gj+jLdy7AdBdQBrJmdoWxds2GCplcT3dU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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