SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68beb9f3bb5489d329bfcb6070680eb9bb0d655425ff7669767cc4463f9df30e' 
  AND token = 'YUO395b0k2NHAsrxu78kRTUXfxBHivGgeI0w5Z8uhbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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