SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83dc51972e833d7b6a73566143b216c877eef863cfae64ca2eb6fafd7d32503f' 
  AND token = 'bZsVAWVSHBtCchYwEPo/BMENhuLiBJf8ZssaO3mJLEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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