SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec6dcec9f5c1230696454a3a5572ee118f78c4d2fe4a6c6c50a3652212edc861' 
  AND token = 'BH5pktCmOOZo6TRZkPCrfrLJXjboSgBuHOR6EfwGDVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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