SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae3d670e90923e1e231b7bb72782c1c79b23765616995b16b48c7612afef6e0c' 
  AND token = 'Xp9Kfb9I4/WOmEKUrMwKaOnpyHgnFCJGihUXxx53oAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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