SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '937d1aa6b2c584ce28038b6d3b8dbbdc193385dd3c9ec64bf2f230175f550f4c' 
  AND token = 'd8a2lsiv8kX5iOyfc/6I2MpUfyr2eK/JEj8osOt2UD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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