SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ffd192081afcab685528f59825e9c1789703ee39db98b5f3ed0811cdc88950c' 
  AND token = 'Ek94ElWPmyDnpecvTdSa+LL3Jk0zlMudvx/Ksf6nVm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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