SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'edb74a16f1b37425074c0ff5c086d07d919fdf2e6db8ae337c30c7e8f1746b52' 
  AND token = 'FfxawYANxJ+g1ZwU1RXpAYvaVxx0a+vtgEr3aPKwVzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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