SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ce7cbf3092499ec0f19785865937f3ef2b8474cb459bbdb32de6fbe197d1c55' 
  AND token = 'kK2VjGWYy7bjMXsaXYKU5Vx67Yc8YAqnUWnQwYWy0K4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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