SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd3170eb513dc147a4d563322b0091b41886e4c5a09f09736c6ab204cfc92d9f' 
  AND token = 'xsgH9DJKJCpyAD8Kskye3OyHMjHjK0osa9vOrxQ5xzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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