SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7321be4e385bdad57773c07dfa5fc3d63f37312c6d16ba9411682d6a3c4b8cbd' 
  AND token = 'FgiGY2+XLV+t2XjsysnDBPiY98Hl7SCcODMRr/9MhZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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