SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5122f8fdf315aec8134b82cb48d31fcefcc75f2cc6825300b07ce554eb91bc24' 
  AND token = 'N9yNk0uQE2Ro0WXIf1a2adUQOL3b3J+UcGhTj4yzTSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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