SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0cf8f768efd01a1230c09361c34f6d7d1489f4ace22c6fe7d73d0adbe5c653d' 
  AND token = '7FSxYdFNBLnyvx6HdZ4Q6bVUqq3lUh4THGhzljCNjXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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