SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ed96d45e295fa3eae4844607d23e13d5fb561742e85ad613cf1a562d169f8a7' 
  AND token = 'ANbySxHQ6L7IZCJVFSWKLpbpX5/+6drsGBAb8OwVGD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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