SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b5971eb86e7e7568e8d1bb2d33b9770798261b8df74323c3238a1165e83de5f' 
  AND token = 'AeO+jivdGjzOK3m3x06tuyo+wLALMaI6NhqwefK2Ke8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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