SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eb2749a39935957edf76279a5310b1eeef566b385847262f148190e939bbe58' 
  AND token = 'XrgRurRlcCPdfxZLG67KmtReSwKOatSupw7InWI0jsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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