SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d0c1424c7f0a98f1ca9541595220bd1161ea1e4d4175f00e4bdf82f32ac7517' 
  AND token = 'lSr35OXsB/SGHZ+pWvEzG+CdlVZKo+Vv4o8aCVxAC9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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