SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bde350eb163ef89680c7c1316b2c0a1a96ca39a2d92a89570d964333fbf5ae22' 
  AND token = 'BV3HTnp224jt5ACpctezojgsvk/fBB8QkumJa6GSPfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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