SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ea31d73ca8bcba02d3b3a3e5985cbbda7137272874dc35ede1f3d326b1e08c2' 
  AND token = 'bXfqViMnNFZAioVZTDtZRqbY+i9UtvKVatVsvJdWEyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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