SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e1a2af5db02c296ed10e528c005ac5295f5bb35bf57ce428d332401d50228a4' 
  AND token = 'M8U1R0DrtsPVDyAkiIy2jpNjLaxY1OVmXCYWUWP/0N4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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