SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3b85ab14c6669681c06e971ce681743aa84306ea49f75f5f1e47fae1096b27c' 
  AND token = 'WU49s3qMNh8jYpCrPePrd2WZ5uFDnoQwA0QdnGIIjX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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