SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71c97467cbbe34f30fc6326aa8c5c0d3902aed7a3ae05928cf4b174217af6eb2' 
  AND token = '+hJEhYK5s+whIdVRgDvNJliLDJYGcihR+tVAlyX4OkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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