SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fab7d31dbfd432b54d3e85d35b8fd562dcff0830a786243d4ba2940b444f1aa3' 
  AND token = 's3qhs9yaRbxvetlodID5JQX6GUqcLNq+e09cbctn+Ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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