SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70e5e4109c8762301d9bfe681ec54c5cc5bf1d6bcb9128cb14b5a3cdae3f2081' 
  AND token = 'wVTu17MkdPI+wLRr1Nk9kf/XXQAYFkecOhoIk2jhxaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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