SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '483ea0249a7c39c43ac330d06a82f00520538b22459b0813c6bb3d7983daeb64' 
  AND token = 'u8WOceU+n4NOcOWwS9bnZs5xZz7o4wukYRg/PpgVOcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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