SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e22011d6e8dcace73886e1a0051424556bce88d37317e1cd16d9476f6109974' 
  AND token = 'XRt0KJxNIOv44ANq+67fl2txJ2KEUe5BeZyAVekCpUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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