SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7db79260afcd03aa99f217811c6df869d48cd6735edd2a39b09491d485fccb2f' 
  AND token = 'YItU4qFKMRimFXINJq+57vv0Wqtb1H+MOZ6dbw/1CDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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