SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f07e73908b52a5cf718e855302dd72acea1df380c7dc285495659f9ca8aa5c72' 
  AND token = 'NhRs8txn5Lme8pvknSdKjjxG7FMg4Bq9gH4NMPnD998=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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