SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcfc59f338e075695f14868cf484fccd53a648cebe1a830a60ae6a66893b99d1' 
  AND token = '8IpvYl4QCM8/51jOhDz35mXXvNBuSRjCBBe8ZYN61ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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