SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aefddbb3fa23126285e05bd2e77a5262ec6abba6623ebfdba85b87f2be6e1ff0' 
  AND token = 'iXAHJCEbsjJiiD0FMJpORUfJSSbewKUm3GWq/GCxf40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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