SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08f63af206eac07c1fe3bdf7e79b85de4592acaf13d2830d0d47d4911a15be81' 
  AND token = 'dPXZdsw4a4n9Gh7EnkYNgw7xeGpmzJ5ji4i/OUG+nJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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