SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e143eae2775fba4ba3518b91a73e80481b27bb80460808d5a9f288bc2de36d2d' 
  AND token = '7tMJ9Z+MOhusX5jyKGR3OmKFVZhbCJ18pcqYA6V4LVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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