SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a7293157047888ce1b716e48141c7afdc88f7008be9713ad961984dd6595703' 
  AND token = '6z5rCeg+K0T4P2Dk6pmnMgOXISr62KaBkIwsqESv9ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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