SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '151c5ae6ba67582ded8d543cf2a8704c36ed12c19dc7ad2ff73692ac3c2ed7d9' 
  AND token = 'UDzXIDfaucjnlIyQSsm295FSPeAztKzO5GprOA4U26Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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