SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c37d459a7150cd916dd9682f615bda6d9603fbc5a978f2797df78cffede2c9d7' 
  AND token = 'XJtoMaHzzo8Gfrtql67lRW706N8FAaFyS+XjNDBazgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}