SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '868c67794effc189f2412508ff041cc0e36406d2fa6cfc9073c1963594e9c3fd' 
  AND token = 'JJ6jfrv3H6lo1fqTqjLDEcbjxQyUC9kro0vRHik3YG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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