SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67fff43e0df188a512f524f94a291ae7b87cc4ba7d2771af7ce26faf493c31ea' 
  AND token = 'rSxK8yvj5uCERgUhkZwR8+STLnzQUxnTM3FDZB7roE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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