SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6887abdef6598e03335309ecfcbbede8c04140b3fa87f3ed5c3a3831aa2e003a' 
  AND token = 'T0PI1pCdKFw4/LkBTdhs1q4nxNZKk0rGoYxqrVilqWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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