SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '166150ad01584488e75df4aaab20736599556631f2a99608678aee35474c0752' 
  AND token = 'fd5Luj0KNmGjKUwPSOkZJASNt4KkBabEl9sjZELr3g0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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