SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a3a970a9e39d0068d48c656f813a934839c61dab6dc57300cbf1efdadc55384' 
  AND token = 'FDcURpv4y2Wov9pJNaPXagDgl1xSUVgOqwv5p3pRrmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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