SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57696f7d60a32dc826bdad0b751a035abdd22ee10bf15f6a211a961491887a75' 
  AND token = 'xlUkVMMSQnjYGdOIcFDTEQacecyNkwHp47lQZ6NgHIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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