SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1621dba137a853d1e43e4630aa67ac5fba4c1e93cd37aa1347ce43228c1f5be' 
  AND token = 'tI8AW+rCSaCt7L/f8Tehtfq6gyHbyWXturg+bdCej7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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