SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb3816aef439990a202466859c7531dd7d2c9dd0265442465af6cff4b9ea023e' 
  AND token = '7VlaFC2ElR3QW4lcpPnQhcmPnkzbqHy9JEXhKo9ayhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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