SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '351b431859e79a9a4916f6b85ac3a4b813efaedd1e06c4c9bef938972e660a55' 
  AND token = 'LoCzIwiHi/UaiGtA9SAT0kJf96aE5kYdPz2rxdvOIpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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