SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23f6367982479321626ba0f27a9294b988981fe0ff0ce8b74e52a51c8d994e44' 
  AND token = 'miax7DIg0qVe05NYOqO/dfr1H+uE3VgbE7rsP29FUjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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