SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7b4c50e42fe64451af58026ea6621b221f834e2984f87fb24fdd63f76f2e8f9' 
  AND token = 'fBBBBmpVZ/Qs5hYHFrFHUXMpg1OIixQbPSz0bHPtwFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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