SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9be713a1932ae89b9f792ccc951c5602d5ee0c432c5ef2ba77324a0a21f1f8d3' 
  AND token = '16029k0YQ06G7PjdgKDtH/s14JAPanBXQqzLyOTaD4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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