SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef376c4f0cdc9e7bb29a4b1e43035712da66685188d10d64412fd7f20cd7ddbf' 
  AND token = 'bvo5HWsODKqrmcuIahl7MGKEdMjB3cV1vCOcv/Yske8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}