SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a237c9dae565e874b771a7958bc63138baa190200acbda497b0142cf3e6fc60' 
  AND token = 'F1SoU5SakBv9gIqgNkHAjRfLRXrxZpYz0XLdsvBQwcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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