SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ef8592878273a276434753ce4860fb68a3492971d33bf683acb07c1f3ac35664' 
  AND token = 'SVhnHv5TnHOIG9gyLRxPfUQUbswica1M9EJTOMJ6ZbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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