SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18012393b5ce3691c02c091dd743a6911c1fc782a3fa5fcb6aecce42416db68d' 
  AND token = 'J3GARZZ10VXX2yViC+5mmXWg4dfznV+Bp452JXCqZ8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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