SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cd5b20e45fd22290b332d76e740338c7af22a9c8bb0323781d7eef674f99324' 
  AND token = '9KDMZpgh2zqjsq13Gc7rBHsAGCmknNMY+4rjg9gp5qw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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