SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4028c542b998d17cf989af4604a5b8619767ebb76bbfd60d9447cf5e6f2d9c66' 
  AND token = 'MffnGrYxbdFrHlq1gWNPqzui5OXSC2vtpOQRkABKrhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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