SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a101da1b4cc3e201931bb9713c55778e9e70d23d6d7d0453edd86c1cb4496c6a' 
  AND token = '6TOIuvPTo+ybzmpeJkpCixcRRpC4JfSPGhNxpHeoUmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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